Disc recording/reproducing device and disc recording/reproducing method

ABSTRACT

In a disc drive device ( 10 ) described as a specific embodiment of the present invention, AC 0  to AC 14  of ADIP cluster address are associated with address bits AU 6  to AU 20  of an address unit. On the basis of 8-bit sector address on the lower side of cluster address arranged in ADIP address of a conventional MD, 0/1 representing sector address FC to 0D of a former-half cluster and sector address 0E to 1F of a latter-half cluster of a sector of a next-generation MD(1) is associated with address bit AU 5  of the address unit. To a part ( 110 ) of 4 address bits AU 4  to AU 1  below this, 4 bits representing individual parts obtained by equally dividing one recording block by 16 are allocated. Thus, a higher-density data volume can be handled without causing any inconvenience while utilizing an existing recording format.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityunder 35 USC §120 from U.S. application Ser. No. 10/478,213, Nov. 28,2003 and claims the benefit of priority under 35 USC §119 from JapanesePatent Application No. P2002-098047, filed on Mar. 29, 2002, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

This invention relates to a disc recording/reproducing device and a discrecording/reproducing method.

This application claims priority of Japanese Patent Application No.2002-098047, filed on Mar. 29, 2002, the entirety of which isincorporated by reference herein.

BACKGROUND ART

As recording media for recording various types of software such as videodata, audio data, or data for computers, recording media such asmagnetic disks, optical discs and magneto-optical discs have beenpopularized. For these recording media, various formats are prescribedby predetermined standards.

In recent years, the advancement of the high-efficiency coding techniquehas enabled band compression of all kinds of data including video dataso that these data are handled as digital data. Along with this,increase in capacity of recording media and improvement in recordingdensity are demanded. As techniques for realizing a higher density ofrecording data, narrowing of the track pitch, change of the linearvelocity, change of the modulation system and the like may beconsidered.

However, in the case of increasing the recording capacity by changingthe recording density of an existing recording medium, the addressmanagement method on the disc differs depending on the recording format.

For example, with an existing magneto-optical disc, in the case ofrecording data at a high density using a different recording format, thequantity of recording data increases and therefore a problem arises thatclusters/sectors represented by ADIP (address in pre-groove) addressesrecorded in advance on grooves of the magneto-optical disc do notcoincide with data blocks, which are actually handled asrecording/reproducing units.

Random access is carried out with reference to ADIP address. Whenreading out data in random access, it is possible to read out desiredrecorded data by accessing a part near the position where the desireddata is recorded. However, when writing data, it is necessary to accessan accurate position in order not to overwrite and erase alreadyrecorded data. Therefore, it is important to accurately grasp the accessposition from the cluster/sector of each data block unit associated withADIP address.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a discrecording/reproducing device and a disc recording reproducing methodthat enable handling of the data volume with a higher density withoutcausing any inconvenience while utilizing the existing recordingformats, in the case of recording data onto a recording medium usingplural recording formats.

A disc recording/reproducing device according to the present inventionis adapted for, with respect to a disc on which a unit cluster having apredetermined number 2N (where N is a positive integer) of sectors as aset is formed and on which a sector address corresponding to each sectorand a cluster address corresponding each cluster are modulated in apredetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing device includes:reproduction means for reproducing the cluster address and the sectoraddress modulated in the predetermined manner and recorded in advance,from the disc; identifier generation means for generating an identifierthat identifies the former N sectors or the latter N sectors obtained bybisecting the cluster unit, as a recording unit used for recording data;recording means for blocking inputted data into plural blocks andrecording the blocked data within the N-sector recording unit; addressgeneration means for generating an address corresponding to the pluralblocks each that are formed in the N-sector recording unit; andconversion means for converting the cluster address and the sectoraddress reproduced by the reproducing means to an address unit includingthe identifier generated by the identifier generation means, the addressgenerated by the address generation means and a recording block addressgenerated on the basis of the cluster address; the address unit obtainedby conversion by the conversion means being recorded for the pluralblocks each, by the recording means.

This disc recording/reproducing device further includes generation meansfor generating an identifier that identifies a recording area when thedisc has plural recording areas, and the identifier generated by thegeneration means is added to the address unit by the conversion meansand thus recorded. Moreover, in this disc recording/reproducing device,the identifier generated by the generation means has a fixed value whenthe disc has a single recording area.

Another disc recording/reproducing device according to the presentinvention is adapted for, with respect to a disc on which a unit clusterhaving a predetermined number 2N (where N is a positive integer) ofsectors added to a linking sector longer than an interleave length as aset is formed and on which a sector address corresponding to each sectorand a cluster address corresponding each cluster are modulated in apredetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing device includes:reproduction means for reproducing the cluster address and the sectoraddress modulated in the predetermined manner and recorded in advance,from the disc; recording means for blocking inputted data into pluralblocks and recording the blocked data within the N-sector recordingunit; address generation means for generating an address correspondingto the plural blocks each that are formed in the N-sector recordingunit; and conversion means for converting the cluster address and thesector address reproduced by the reproducing means to an address unitincluding the address generated by the address generation means and arecording block address generated on the basis of the cluster address;the address unit obtained by conversion by the conversion means beingrecorded for the plural blocks each, by the recording means.

This disc recording/reproducing device further includes generation meansfor generating an identifier that identifies a recording area when thedisc has plural recording areas, and the identifier generated by thegeneration means is added to the address unit by the conversion meansand thus recorded. Moreover, in this disc recording/reproducing device,the identifier generated by the generation means has a fixed value whenthe disc has a single recording area.

A disc recording/reproducing method according to the present inventionis adapted for, with respect to a disc on which a unit cluster having apredetermined number 2N (where N is a positive integer) of sectors as aset is formed and on which a sector address corresponding to each sectorand a cluster address corresponding each cluster are modulated in apredetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing method includes: a stepof reproducing the cluster address and the sector address modulated inthe predetermined manner and recorded in advance, from the disc; a stepof generating an identifier that identifies the former N sectors or thelatter N sectors obtained by bisecting the cluster unit, as a recordingunit used for recording data; a step of generating an addresscorresponding to the plural blocks each that are formed in the N-sectorrecording unit; a step of converting the reproduced cluster address andsector address to an address unit including the generated identifier,the generated address and a recording block address generated on thebasis of the cluster address; and a step of blocking inputted data intoplural blocks, then recording the blocked data in the N-sector recordingunit, and recording the address unit obtained by the conversion for theplural blocks each.

Another disc recording/reproducing method according to the presentinvention is adapted for, with respect to a disc on which a unit clusterhaving a predetermined number 2N (where N is a positive integer) ofsectors added to a linking sector longer than an interleave length as aset is formed and on which a sector address corresponding to each sectorand a cluster address corresponding each cluster are modulated in apredetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing method includes: a stepof reproducing the cluster address and the sector address modulated inthe predetermined manner and recorded in advance, from the disc; a stepof generating an address corresponding to the plural blocks each thatare formed in the N-sector recording unit; a step of converting thereproduced cluster address and sector address to an address unitincluding the generated address and a recording block address generatedon the basis of the cluster address; and a step of blocking inputteddata into plural blocks, then recording the blocked data within theN-sector recording unit, and recording the address unit obtained by theconversion for the plural blocks each.

The other objects of the present invention and specific advantagesprovided by the present invention will be further clarified from thefollowing description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view for explaining the specifications of a next-generationMD1 and a next-generation MD2 described as specific examples of thepresent invention, and a conventional mini disc.

FIG. 2 is a view for explaining an RS-LDC block with BIS of an errorcorrecting system in the next-generation MD1 and the next-generation MD2described as specific examples of the present invention.

FIG. 3 is a view for explaining the BIS arrangement in one recordingblock of the next-generation MD1 and the next-generation MD2 describedas specific examples of the present invention.

FIG. 4 is a schematic view for explaining the area structure on the discsurface of the next-generation MD1 described as a specific example ofthe present invention.

FIG. 5 is a schematic view for explaining the area structure on the discsurface of the next-generation MD2 described as a specific example ofthe present invention.

FIG. 6 is a schematic view for explaining the area structure on the discsurface in the case where audio data and PC data are recorded in a mixedmanner on the next-generation MD1 described as a specific example of thepresent invention.

FIG. 7 is a schematic view for explaining the data management structureof the next-generation MD1 described as a specific example of thepresent invention.

FIG. 8 is a schematic view for explaining the data management structureof the next-generation MD2 described as a specific example of thepresent invention.

FIG. 9 is a schematic view for explaining the relation between an ADIPsector structure and a data block of the next-generation MD1 and thenext-generation MD2 described as specific example of the presentinvention.

FIG. 10A is a schematic view showing the ADIP data structure of thenext-generation MD2. FIG. 10B is a schematic view showing the ADIP datastructure of the next-generation MD1.

FIG. 11 is a schematic view for explaining a modification of the datamanagement structure of the next-generation MD2 described as a specificexample of the present invention.

FIG. 12 is a block diagram for explaining a disc drive device forperforming recording and reproduction compatible with thenext-generation MD1 and the next-generation MD2 described as specificexample of the present invention.

FIG. 13 is a block diagram for explaining a medium drive unit of thedisc drive device.

FIG. 14 is a flowchart for explaining sector reproduction processing ofthe next-generation MD1 and the next-generation MD2 in the disc drivedevice.

FIG. 15 is a flowchart for explaining sector recording processing of thenext-generation MD1 and the next-generation MD2 in the disc drivedevice.

FIG. 16 is a view for explaining the relation between an ADIP addressand an address unit of the next-generation MD1 described as a specificexample of the present invention.

FIG. 17 is a view for explaining the relation between an ADIP addressand an address unit of the next-generation MD2 described as a specificexample of the present invention.

FIG. 18 is a view for explaining scrambling processing of a logicalsector of the next-generation MD1 described as a specific example of thepresent invention.

FIG. 19 is a view for explaining scrambling processing of a logicalsector of the next-generation MD2 described as a specific example of thepresent invention.

FIG. 20 is a circuit diagram for realizing address unit conversionaccording to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Specific embodiments of the present invention will now be described withreference to the drawings.

The present invention provides an address conversion method forperforming conversion from one address to another address between afirst address set for data and a second address set for a recordingformat on a recording medium. At least part of the second address iscaused to correspond to a part of the first address. A part lower thanleast significant position of the part of the first address is generatedin accordance with a predetermined rule, and a part higher than the mostsignificant position of the part of the first address is extended bypredetermined digit(s) so that the first address and the second addresscorrespond to each other. In the case of recording data in pluralrecording formats to the recording medium, it is practically possible tohandle a data volume with a higher density without causing anyinconvenience while utilizing the existing recording format.

In this disc drive device, a signal format that is different from anordinary recording format used as a recording/reproducing format for adisc-like recording medium employing a conventional magneto-opticalrecording system is applied to this disc-like recording medium, thusrealizing increase in recording capacity of the conventionalmagneto-optical recording medium. Moreover, as a high-density recordingtechnique and a new file system are used, a recording format is providedthat enables significant increase in recording capacity whilemaintaining the compatibility of the appearance of casing and therecording/reproducing optical system with those of the conventionalmagneto-optical recording medium.

In this specific embodiment, as a disc-like magneto-optical recordingmedium, a recording medium of the mini disc (trademark registered)system is used. Particularly, a disc that has realized increase inrecording capacity of the conventional magneto-optical recording mediumby employing a format that is different from an ordinarily usedrecording format will be explained as “next-generation MD1”, and a discthat has realized increase in recording capacity by applying a newrecording format to a new recording medium capable of high-densityrecording will be explained as “next-generation MD2”.

Hereinafter, exemplary specifications of the next-generation MD1 and thenext-generation MD2 will be described, and processing to generaterecording data for both discs using an address conversion methodaccording to the present invention will also be described.

1. Disc Specifications and Area Structure

First, the specifications of the conventional mini disc, thenext-generation MD1 and the next-generation MD2 will be described withreference to FIG. 1. The physical format of the mini disc (and MD-DATA)is defined as follows. The track pitch is 1.6 μm. The bit length is 0.59μm/bit. The laser wavelength λ is λ=780 nm. The numerical aperture ofthe optical head is NA=0.45. As its recording system, a groove recordingsystem used for recording and reproduction based on grooves (on the discsurface) as tracks is employed. In an address system for this, asingle-spiral groove is formed on the disc surface, a meandering wobbleis formed on both sides of the groove at a predetermined frequency(22.05 kHz), and an absolute address is FM-modulated with reference tothe above-mentioned frequency and recorded to the wobbled groove track.In this specification, the absolute address recorded as a wobble is alsoreferred to as ADIP (address in pre-groove).

On the conventional MD, recording is performed using 32 sectors as amain data part and 4 sectors as link sectors, that is, a total of 36sectors, as one cluster unit. The ADIP signal includes a cluster addressand a sector address. The cluster address includes an 8-bit cluster Hand an 8-bit cluster L. The sector address includes a 4-bit sector.

For the conventional mini disc, an EFM (8-14 modulation) modulationsystem is employed as a recording data modulation system. As its errorcorrecting system, ACIRC (advanced cross interleave Reed-Solomon code)is used. For data interleave, convolution is employed. Therefore, theredundancy of data is 46.3%.

The data detecting system on the conventional mini disc is a bit-by-bitsystem. As its disc driving system, a CLV (constant linear velocity)system is used. The constant linear velocity is 1.2 m/s.

The standard data rate in recording and reproduction is 133 KB/s. Therecording capacity is 164 MB (140 MB for MD-DATA). The minimum rewritingunit (unit cluster) of data includes 36 sectors, that is, 32 mainsectors and 4 link sectors, as described above.

Next, the next-generation MD1 described as the specific embodiment willbe described. The next-generation MD1 has the same physicalspecifications as the above-described conventional mini disc. Therefore,the track pitch is 1.6 μm. The laser wavelength λ is λ=780 nm. Thenumerical aperture of the optical head is NA=0.45. As its recordingsystem, the groove recording system is employed. As its address system,ADIP is used. Since the structure of the optical system in the discdrive device, the ADIP address reading system and the servo processingare the same as those for the conventional mini disc, compatibility withthe conventional disc is achieved.

As the modulation system for recording data, the next-generation MD1employs an RLL(1-7)PP modulation system (where RLL represents “runlength limited” and PP represents “parity preserve/prohibit rmtr(repeated minimum transition runlength)”). As its error correctingsystem, an RS-LDC (Reed Solomon-long distance code) system with BIS(burst indicator subcode) having higher correction capability is used.

Specifically, 2052 bytes, including 2048 bytes of user data suppliedfrom a host application or the like and an EDC (error detection code) of4 bytes, are handled as 1 sector (that is, a data sector different froma physical sector on the disc, which will be described later), and 32sectors of sector 0 to sector 31 are grouped into a block consisting of304 columns×216 rows, as shown in FIG. 2. Scrambling processing to takeexclusive OR (EX-OR) with a predetermined pseudo-random number isperformed to 2052 bytes of each sector. To each column of the block towhich scrambling processing has been thus performed, a 32-byte parity isadded to constitute an LDC (long distance code) block of 304 columns×248rows. Interleave processing is performed to this LDC block to form ablock (interleaved LDC block) of 152 columns×496 rows, and one column ofthe above-described BIS is arranged every 38 columns, thus forming astructure consisting of 155 columns×496 rows, as shown in FIG. 3.Moreover, a frame synchronizing code (frame sync) of 2.5 bytes is addedto the leading end position, and each row is caused to correspond to oneframe, thus forming a structure consisting of 157.5 bytes×496 frames.The respective rows of FIG. 3 are equivalent to 496 frames of frame 10to frame 505 of a data area in one recording block (cluster) shown inFIG. 9, which will be described later.

In the above-described data structure, data interleave is ofblock-completion type. This allows data redundancy of 20.50%. As thedata detecting system, a Viterbi decoding system based on PR(1, 2, 1)MLis used.

For the disc driving system, the CLV system is used with a linearvelocity is 2.4 m/s. The standard data rate in recording andreproduction is 4.4 MB/s. As this system is employed, a total recordingcapacity of 300 MB can be secured. Since the modulation system ischanged from the EFM modulation system to the RLL(1-7)PP modulationsystem, the window margin is increased from 0.5 to 0.666 and therefore ahigher density by 1.33 times can be realized. A cluster, which is theminimum data rewriting unit, includes 16 sectors, 64 KB. Since therecording modulation system is thus changed from the CIRC system to theRS-LDC system with BIS and the system using the difference in sectorstructure and Viterbi decoding, the data efficiency is improved from53.7% to 79.5% and therefore a higher density by 1.48 times can berealized.

By combining these, the next-generation MD1 can realize a recordingcapacity of 300 MB, which is approximately twice the recording capacityof the conventional mini disc.

On the other hand, the next-generation MD2 is a recording medium towhich a higher-density recording technique such as a domain walldisplacement detection system (DWDD) is applied. The next-generation MD2has a physical format that is different from those of theabove-described conventional mini disc and next-generation MD1. Thenext-generation MD2 has a track pitch of 1.25 μm and a bit length of0.16 μm/bit, and has a higher density in a linear direction.

To achieve compatibility with the conventional mini disc and thenext-generation MD1, the optical system, the reading system, the servoprocessing and the like are made conformable to the conventionalstandards, that is, laser wavelength λ=780 nm and numerical aperture ofthe optical head NA=0.45. The recording system is the groove recordingsystem. The address system is the system using ADIP. The casingappearance is also made conformable to the standards of the conventionalmini disc and the next-generation MD1.

However, when reading a narrow track pitch and linear density (bitlength) than in the conventional technique as described above using anoptical system equivalent to that of the conventional mini disc or thenext-generation MD1, it is necessary to solve restraining conditions inde-tracking margin, cross talk from lands and grooves, cross talk ofwobbles, focusing leakage, and CT signal. Therefore, the next-generationMD2 is characterized in that the depth, gradient, width and the like ofthe groove are changed. Specifically, the depth of the groove is definedwithin a range of 160 to 180 nm. The gradient is defined within a rangeof 60 to 70°. The width is defined within a range of 600 to 800 nm.

The next-generation MD2 employs the RLL(1-7)PP modulation system (whereRLL represents “run length limited” and PP represents “paritypreserve/prohibit rmtr (repeated minimum transition runlength)”) adaptedfor high-density recording, as the modulation system for recording data.As the error correcting system, the RS-LDC (Reed Solomon-long distancecode) system with BIS having higher correction capability is used.

Data interleave is of block-completion type. This allows data redundancyof 20.50%. The data detecting system is the Viterbi decoding systembased on PR(1, −1)ML. A cluster, which is the minimum data rewritingunit, includes 16 sectors, 64 KB.

As the disc driving system, a ZCAV (zone constant angular velocity)system is used with a linear velocity of 2.0 m/s. The standard data ratein recording and reproduction is 9.8 MB/s. Therefore, thenext-generation MD2 can achieve a total recording capacity of 1 GB byemploying the DWDD system and this driving system.

FIGS. 4 and 5 show an exemplary area structure on the disc surface ofthe next-generation MD1 of this specific embodiment. The next-generationMD1 is the same medium as the conventional mini disc. On the innermostcircular side of the disc, PTOC (premastered table of contents) isprovided as a premastered area. In this area, disc managementinformation is recorded as embossed pits based on physical structuraldeformation.

On the circular side outer than the premastered area, a recordable areais provided in which magneto-optical recording can be made. This is arecordable/reproducible area in which a groove as a guide groove to arecording track is formed. On the innermost circular side of thisrecordable area, a UTOC (user table of contents) area is provided. Inthis UTOC area, UTOC information is described, and a buffer area withrespect to the premastered area and a power calibration area used foroutput power adjustment of a laser beam or the like are provided.

The next-generation MD2 uses no pre-pits to realize a higher density, asshown in FIG. 5. Therefore, the next-generation MD2 has no PTOC area. Onthe next-generation MD2, a unique ID (UID) area to record informationfor copyright protection, information for checking data falsification,other non-public information and the like is provided in an area innerthan the recordable area. In this UID area, information is recorded in arecording format that is different from the DWDD system applied to thenext-generation MD2.

On the next-generation MD1 and the next-generation MD2, audio tracks formusic data and data tracks can be recorded in a mixed manner. In thiscase, an audio recording area AA in which at least one audio track isrecorded and a PC data recording area DA in which at least one datatrack is recorded are formed at arbitrary positions in the data area,for example, as shown in FIG. 6.

A series of audio track and data track need not necessarily recorded ina physically continuous manner on the disc but may be dividedly recordedas plural parts as shown in FIG. 6. Parts means sections that arerecorded in a physically continuous manner. Specifically, even whenthere are two PC data recording areas that are physically separate asshown in FIG. 6, the number of data tracks may be one or plural. WhileFIG. 6 shows the physical specifications of the next-generation MD1, theaudio recording area AA and the PC data recording area DA can besimilarly recorded on the next-generation MD2 in a mixed manner.

A specific example of a recording/reproducing device compatible with thenext-generation MD1 and the next-generation MD2 having theabove-described physical specifications will be later described indetail.

2. Management Structure of Disc

The management structure of the disc of this specific embodiment will bedescribed with reference to FIGS. 7 and 8. FIG. 7 shows the datamanagement structure of the next-generation MD1. FIG. 8 shows the datamanagement structure of the next-generation MD2.

Since the next-generation MD1 is the same medium as the conventionalmini disc as described above, PTOC is recorded on the next-generationMD1 in the form of embossed pits that cannot be rewritten, as employedin the conventional mini disc. In this PTOC, the total capacity of thedisc, the UTOC position in the UTOC area, the position of the powercalibration area, the start position of the data area, the end positionof the data area (lead-out position) and the like are recorded asmanagement information.

On the next-generation MD1, the power calibration area (rec powercalibration area) for adjusting the writing output of a laser isprovided at ADIP addresses 0000 to 0002. At the subsequent addresses0003 to 0005, UTOC is recorded. UTOC includes management informationthat is rewritten in accordance with recording, erasure and the like oftracks (audio track/data track) and manages the start position, the endposition and the like of the respective tracks and parts constitutingthe tracks. UTOC also manages parts in a free area in which no track hasbeen recorded yet, that is, a writable area. In UTOC, the whole PC datais managed as one track independent of MD audio data. Therefore, even ifan audio track and a data track are recorded in a mixed manner, therecording positions of PC data divided into plural parts can be managed.

UTOC data is recorded in a specified ADIP cluster in this UTOC area. Thecontent of the UTOC data is defined by each sector in this ADIP cluster.Specifically, UTOC sector 0 (the leading ADIP sector in this ADIPcluster) manages parts corresponding to the tracks and free area. UTOCsector 1 and UTOC sector 4 manages character information correspondingto the tracks. In UTOC sector 2, information for managing the recordingdate and time corresponding to the tracks is written.

UTOC sector 0 is a data area in which recorded data, recordablenon-recorded area, data management information and the like arerecorded. For example, when recording data to the disc, the disc drivedevice finds out a non-recorded area on the disc from the UTOC sector 0and records data into this area. In reproduction, the disc drive devicejudges, from UTOC sector 0, the area where a data track to be reproducedis recorded, and accesses that area to perform reproduction.

On the next-generation MD1, PTOC and UTOC are recorded as data modulatedin accordance with a system conformable to the conventional mini discsystem, that is, in this case, the EFM modulation system. Therefore, thenext-generation MD1 has an area where data modulated in accordance withthe EFM modulation system is recorded, and an area where high-densitydata modulated in accordance with the RS-LDC and RLL(1-7)PP modulationsystems is recorded.

An alert track described at ADIP address 0032 stores information fornotification to the effect that the next-generation MD1 is not supportedby a disc driver device for the conventional mini disc even when thenext-generation MD1 is inserted into the disc driver device for theconventional mini disc. This information may be audio data that says“The format of this disc is not supported by this reproducing device,”or warning sound data. In the case of a disc driver device having adisplay unit, this information may be data for displaying thenotification. This alert track is recorded in accordance with the EFMmodulation system so that it can be read by the disc driver devicecorresponding to the conventional mini disc.

At ADIP address 0034, a disc description table (DDT) describing discinformation of the next-generation MD1 is recorded. In DDT, the format,the total number of logical clusters on the disc, proper ID of themedium, update information of this DDT, defective cluster informationand the like are described.

In the DDT area and subsequent areas, data is recorded as high-densitydata modulated in accordance with the RS-LDC and RLL(1-7)PP modulationsystems. Therefore, a guard band area is provided between the alerttrack and DDT.

At the earliest ADIP address where high-density data modulated by theRLL(1-7)PP modulation system is recorded, that is, at the leadingaddress of DDT, a logical cluster number (LCN) is appended, whichdefines this address as 0000. One logical cluster includes 65,536 bytes.This logical cluster is a minimum unit for reading/writing. ADIPaddresses 0006 to 0031 are reserved.

At the subsequent ADIP addresses 0036 to 0038, a secure area isprovided, which can be made public by authentication. This secure areamanages attributes representing whether the respective clustersconstituting data can be made public or not. Particularly, informationfor copyright protection, information for checking data falsificationand the like are recorded in this secure area. Various other non-publicinformation can be recorded, too. This non-public area allows limitedaccess by a specially permitted specific external device, and alsoincludes information for authenticating this external device that isallowed to access this area.

At ADIP address 0038 and the subsequent ADIP addresses, a user area(with an arbitrary data length) where writing and reading can be freelycarried out, and a spare area (with a data length 8) are described. Datarecorded in the user area, when arrayed in LCN ascending order, issectioned into user sectors in which 2,048 bytes from the leading endform one unit. An external device such as PC manages this data byappending a user sector number (USN) of 0000 for the leading user sectorand using an FAT file system.

The data management structure of the next-generation MD2 will now bedescribed with reference to FIG. 8. The next-generation MD2 has no PTOC.Therefore, all the disc management information such as the totalcapacity of the disc, the position of the power calibration area, thestart position of the data area and the end position of the data area(lead-out position) is included as PDPT (preformat disc parameter table)in ADIP information and thus recorded. Data is modulated in accordancewith the RS-LDC modulation system with BIS and the RLL(1-7)PP modulationsystem and recorded in the DWDD format.

In a lead-in area and a lead-out area, the laser power calibration area(PCA) is provided. On the next-generation MD2, LCN 0000 is appended toan ADIP address following PCA.

On the next-generation MD2, a control area equivalent to the UTOC areaof the next-generation MD1 is prepared. FIG. 8 shows a unique ID (UID)area where information for copyright protection, information forchecking data falsification and other non-public information arerecorded. Actually, this UID area is provided at a position inner thanthe lead-in area, and data is recorded therein in a recording formatthat is different from the ordinary DWDD format.

Files of the next-generation MD1 and the next-generation MD2 are managedon the basis of FAT file systems. For example, the respective datatracks have individual FAT file systems. Alternatively, one FAT filesystem may be recorded to cover plural data tracks.

3. ADIP Sector/Cluster Structure and Data Block

The relation between the ADIP sector structures and data blocks of thenext-generation MD1 and the next-generation MD2 described in thespecific embodiment of the present invention will now be described withreference to FIG. 9. The conventional mini disc (MD) system employs acluster/sector structure corresponding to the physical address recordedas ADIP. In this embodiment, a cluster based on the ADIP address isreferred to as “ADIP cluster”, as a matter of convenience. A clusterbased on the address on the next-generation MD1 and the next-generationMD2 is referred to as “recording block” or “next-generation MD cluster”.

On the next-generation MD1 and the next-generation MD2, a data track ishandled as a data stream recorded in the form of continuous clusters,which are minimum units of address, as shown in FIG. 9.

As shown in FIG. 9, in the case of the next-generation MD1, oneconventional cluster (36 sectors) is bisected so that one recordingblock consists of 18 sectors. In the case of the next-generation MD2,one recording block consists of 16 sectors.

The data structure of one recording block (one next-generation MDcluster) shown in FIG. 9 includes 512 frames, that is, a preamble madeup of 10 frames, a postamble made up of 6 frames, and a data part madeup of 496 frames. One frame in this recording block includes asynchronizing signal area, data, BIS and DSV.

Of the 512 frames of one recording block, each of groups of framesobtained by equally dividing 496 frames where main data is recorded into16 is referred to as address unit. Each address unit includes 31 frames.The number of this address unit is referred to as address unit number(AUN). This AUN is a number appended to all address units and is usedfor address management of recording signals.

In the case of recording high-density data modulated in accordance withthe 1-7PP modulation system to the conventional mini disc having thephysical cluster/sector structure described in ADIP as in thenext-generation MD1, a problem arises that the ADIP address originallyrecorded on the disc and the address of the actually recorded data blockdo not coincide with each other. In random access, which is carried outwith reference to the ADIP address, even if a position near the positionwhere desired data is recorded is accessed when reading out data, therecorded data can be read out. However, when writing data, it isnecessary to access an accurate position so as not to overwrite anderase already recorded data. Therefore, it is important to accuratelygrasp the access position from the next-generation MDcluster/next-generation MD sector corresponding to the ADIP address.

Thus, in the case of the next-generation MD1, the high-density datacluster is grasped, using a data unit obtained by converting the ADIPaddress recorded as a wobble on the medium surface in accordance with apredetermined rule. In this case, an integral multiple of the ADIPsector is caused to be the high-density data cluster. On the basis ofthis idea, when describing the next-generation MD cluster with respectto one ADIP cluster recorded on the conventional mini disc, eachnext-generation MD cluster is caused to correspond to a ½-ADIP cluster(18 sectors).

Therefore, in the case of the next-generation MD1, a ½-cluster of theconventional MD cluster is handled as a minimum recording unit(recording block).

On the other hand, in the case of the next-generation MD2, one clusteris handled as one recording block.

In this specific embodiment, a data block made up of 2048 bytes as aunit supplied from the host application is handled as one logical datasector (LDS), and a set of 32 logical data sectors recorded in the samerecording block is handled as a logical data cluster (LDC), as describedabove.

With the data structure as described above, when recordingnext-generation MD data to an arbitrary position, recording to themedium at good timing can be realized. Moreover, as an integral numberof next-generation MD clusters are included in an ADIP cluster, which isan ADIP address unit, the address conversion rule for converting theADIP cluster address to the next-generation MD data cluster address issimplified and the circuit or software structure for the conversion canbe simplified.

While two next-generation MD clusters are caused to correspond to oneADIP cluster in the example shown in FIG. 9, three or morenext-generation MD clusters can be arranged with respect to one ADIPcluster. In this case, one next-generation MD cluster is not limited tothe construction made up of 16 ADIP sectors. The next-generation MDcluster can be set in accordance with the difference in data recordingdensity between the EFM modulation system and the RLL(1-7)PP modulationsystem, the number of sectors constituting a next-generation cluster,the size of one sector and the like.

While FIG. 9 shows the data structure on the recording medium, a datastructure in the case where an ADIP signal recorded on a groove wobbletrack on the recording medium is demodulated by an ADIP demodulator 38of FIG. 13, which will be described later, will now be explained.

FIG. 10A shows the data structure of ADIP of the next-generation MD2.FIG. 10B shows the data structure of ADIP of the next-generation MD1.

In the case of the next-generation MD1, a synchronizing signal, clusterH information and cluster L information representing cluster numbers onthe disc, sector information including sector numbers in the cluster aredescribed. The synchronizing signal is described by 4 bits. The clusterH is described by upper 8 bits of address information. The cluster L isdescribed by lower 8 bits of the address information. The sectorinformation is described by 8 bits. CRC is added to the latter 14 bits.In this manner, an ADIP signal of 42 bits is recorded in each ADIPsector.

In the case of the next-generation MD2, synchronizing signal data of 4bits, cluster H information of 4 bits, cluster M information of 8 bits,cluster L information of 4 bits, and sector information of 4 bits aredescribed. A BCH parity is added to the latter 18 bits. Also in the caseof the next-generation MD2, an ADIP signal of 42 bits is similarlyrecorded in each ADIP sector.

In the data structure of ADIP, the construction of the above-describedcluster H information, cluster M information and cluster L informationcan be arbitrarily decided. Alternatively, other additional informationcan be described in this part. For example, in an ADIP signal on thenext-generation MD2, cluster information is represented by a cluster Hof upper 8 bits and a cluster L of lower 8 bits, as shown in FIG. 11,and disc control information can be described instead of the cluster Lof lower 8 bits. The disc control information may be a servo signalcorrection value, upper limit value of reproducing laser power, linearvelocity correction coefficient for reproducing laser power, upper limitvalue of recording laser power, linear velocity correction coefficientfor recording laser power, recording magnetic sensitivity,magnetism-laser pulse phase difference, parity and the like.

4. Disc Drive Device

A specific example of a disc drive device 10 capable of performingrecording and reproduction of the next-generation MD1 and thenext-generation MD2 will be described with reference to FIGS. 12 and 13.The disc drive device 10 can be connected to a personal computer(hereinafter referred to as PC) 100 and can use the next-generation MD1and the next-generation MD2 as external storage for audio data and forPC and the like.

The disc drive device 10 has a medium drive unit 11, a memory transfercontroller 12, a cluster buffer memory 13, an auxiliary memory 14, USBinterfaces 15, 16, a USB hub 17, a system controller 18, and an audioprocessing unit 19.

The medium drive unit 11 performs recording to/reproduction from anindividual disc 90 loaded thereon such as the conventional mini disc,the next-generation MD1 or the next-generation MD2. The internalstructure of the medium drive unit 11 will be described later withreference to FIG. 13.

The memory transfer controller 12 controls transmission/reception ofreproduction data from the medium drive unit 11 and recording data to besupplied to the medium drive unit 11. The cluster buffer memory 13buffers data read out by each high-density data cluster from a datatrack of the disc 90 by the medium drive unit 11, under the control ofthe memory transfer controller 12. The auxiliary memory 14 storesvarious management information and special information such as UTOCdata, CAT data, unique ID and hash value read out from the disc by themedium drive unit 11, under the control of the memory transfercontroller 12.

The system controller 18 can communicate with the PC 100 connected viathe USB interface 16 and the USB hub 17. The system controller 18controls communication with the PC 100, performs reception of commandssuch as a writing request and a reading request and transmission ofstatus information and other necessary information, and integrallycontrols the whole disc drive device 10.

For example, when the disc 90 is loaded on the medium drive unit 11, thesystem controller 18 instructs the medium drive unit 11 to read outmanagement information and the like from the disc 90 and causes thememory transfer controller 12 to control the auxiliary memory 14 tostore the read-out management information and the like such as PTOC andUTOC.

By reading the management information, the system controller 18 cangrasp the track recording state of the disc 90. Moreover, by readingCAT, the system controller 18 can grasp the high-density data clusterstructure within the data track and can be ready to respond to an accessrequest for the data track from the PC 100.

With the unique ID and the hash value, the system controller 18 executesdisc authentication processing and other processing, transmits thesevalues to the PC 100, and causes the disc authentication processing andother processing to be executed on the PC 100.

When a reading request for a certain FAT sector is sent from the PC 100,the system controller 18 gives the medium drive unit 11 a signal forreading out a high-density data cluster containing this FAT sector. Theread-out high-density data cluster is written to the cluster buffermemory 13 by the memory transfer controller 12. However, if the data ofthe FAT sector has already been stored in the cluster buffer memory 13,the medium drive unit 11 need not read out the data.

In this case, the system controller 18 performs control to give a signalfor reading out the data of the requested FAT sector from the data ofthe high-density data cluster that is being written to the clusterbuffer memory 13, and to send the signal to the PC 100 via the USBinterface 15 and the USB hub 17.

When a writing request for a certain FAT sector is sent from the PC 100,the system controller 18 causes the medium drive unit 11 to read out ahigh-density data cluster containing this FAT sector. The read-outhigh-density data cluster is written to the cluster buffer memory 13 bythe memory transfer controller 12. However, if the data of the FATsector has already been stored in the cluster buffer memory 13, themedium drive unit 11 need not read out the data.

The system controller 18 also supplies data of a FAT sector (recordingdata) sent from the PC 100, to the memory transfer controller 12 via theUSB interface 15, and causes the memory transfer controller 12 torewrite the data of the corresponding FAT sector on the cluster buffermemory 13.

The system controller 18 also instructs the memory transfer controller12 to transfer to the medium drive unit 11 the data of the high-densitydata cluster stored in the cluster buffer memory 13 in which therequested FAT sector has been rewritten, as recording data. In thiscase, the medium drive unit 11 modulates and writes the recording dataof the high-density data cluster, in accordance with the EFM modulationsystem if the loaded medium is the conventional mini disc, or inaccordance with the RLL(1-7)PP modulation system if the loaded medium isthe next-generation MD1 or the next-generation MD2.

In the disc drive device 10 described in this embodiment, theabove-described recording/reproduction control is the control in thecase of recording/reproducing a data track. Data transfer inrecording/reproducing an MD audio data (audio track) is performed viathe audio processing unit 19.

The audio processing unit 19 has, for example, an analog audio signalinput part such as a line input circuit/microphone input circuit, an A/Dconverter, and a digital audio data input part, as an input system. Theaudio processing unit 19 also has an ATRAC compression encoder/decoderand a buffer memory for compressed data. The audio processing unit 19also has a digital audio data output part, a D/A converter, and ananalog audio signal output part such as a line output circuit/headphoneoutput circuit, as an output system.

An audio track is recorded onto the disc 90 when digital audio data (oranalog audio signal) is inputted to the audio processing unit 19. Theinputted linear PCM digital audio data, or linear PCM audio dataobtained by converting the inputted analog audio signal at the A/Dconverter, is ATRAC compression-encoded and stored into the buffermemory. After that, the audio data is read out from the buffer memory atpredetermined timing and transferred to the medium drive unit 11.

The medium drive unit 11 modulates the transferred compressed data inaccordance with the EFM modulation system or the RLL(1-7)PP modulationsystem and writes the modulated data to the disc 90 as an audio track.

When reproducing an audio track from the disc 90, the medium drive unit11 demodulates reproduced data to ATRAC compressed data and transfersthe demodulated data to the audio processing unit 19. The audioprocessing unit 19 performs ATRAC compression decoding to obtain linearPCM audio data and outputs the linear PCM audio data from the digitalaudio data output part.

This structure shown in FIG. 12 is simply an example. The audioprocessing unit 19 is not necessary, for example, when the disc drivedevice 10 is connected with the PC 100 and is used as an externalstorage device for recording and reproducing only a data track. On theother hand, when the main purpose is to record and reproduce audiosignals, it is preferred that the audio processing unit 19 is providedand that an operating unit and a display unit as user interfaces areprovided. For the connection with the PC 100, not only USB but also aso-called IEEE1394 interface conformable to the standards prescribed byIEEE (Institute of Electrical and Electronics Engineers) andgeneral-purpose connection interfaces can be applied.

Next, the structure of the medium drive unit 11 for recording andreproduction of the conventional mini disc, the next-generation MD1 andthe next-generation MD2 will be described further in detail withreference to FIG. 13.

The medium drive unit 11 is characterized in that in order to recorddata to and reproduce data from the conventional mini disc, thenext-generation MD1 and the next-generation MD2, it has a structure forexecuting EFM modulation and ACIRC encoding for recording on theconventional mini disc and a structure for executing RLL(1-7)PPmodulation and RS-LDC encoding for recording on the next-generation MD1and the next-generation MD2, particularly as a recording processingsystem. The medium drive unit 11 is also characterized in that it has astructure for executing EFM demodulation and ACIRC decoding forreproduction from the conventional mini disc and a structure forexecuting RLL(1-7) demodulation based on data detection using PR(1, 2,1)ML and Viterbi decoding, and RS-LDC decoding for reproduction from thenext-generation MD1 and the next-generation MD2, as a reproductionprocessing system.

The medium drive unit 11 rotationally drives the loaded disc 90 in theCLV system or the ZCAV system, using a spindle motor 21. In recordingand reproduction, a laser beam is cast on the disc 90 from an opticalhead 22.

In recording, the optical head 22 outputs a laser beam of a high levelfor heating the recording track to the Curie temperature. Inreproduction, the optical head 22 outputs a laser beam of a relativelylow level for detecting data from reflected light by a magnetic Kerreffect. Therefore, the optical head 22 is equipped with an opticalsystem including a laser diode as a laser output unit, a polarizing beamsplitter, an objective lens and like, and a detector for detectingreflected light. The objective lens provided in the optical head 22 isheld in such a manner that it can be displaced in a disc radialdirection and a direction toward/away from the disc, for example, by abiaxial mechanism.

In this specific embodiment, in order to realize a maximum reproducingcharacteristic for the conventional mini disc, the next-generation MD1and the next-generation MD2, which differ in physical specifications ofmedium surface, a phase compensating plate that can optimize the biterror rate at the time of data reading for all the discs is provided inthe optical path of reading light of the optical head 22.

A magnetic head 23 is arranged at a position opposite to the opticalhead 22 with respect to the disc 90. The magnetic head 23 applies amagnetic field modulated by recording data, to the disc 90. Although notshown, a thread motor and a thread mechanism for moving the wholeoptical head 22 and the magnetic head 23 in the disc radial directionare provided.

In this medium drive unit 11, a recording processing system, areproduction processing system, a servo system and the like areprovided, in addition to a recording/reproducing head system includingthe optical head 22 and the magnetic head 23, and a disc rotationaldriving system including the spindle motor 21. As the recordingprocessing system, a part for performing EFM modulation and ACIRCencoding at the time of recording to the conventional mini disc, and apart for performing RLL(1-7)PP modulation and RS-LDC encoding at thetime of recording to the next-generation MD1 and the next-generation MD2are provided.

As the reproduction processing system, a part for performingdemodulation corresponding to EFM modulation and ACIRC decoding at thetime of reproduction from the conventional mini disc, and a part forperforming demodulation corresponding to RLL(1-7)PP modulation (i.e.,RLL(1-7) demodulation based on data detection using PR(1, 2, 1)ML andViterbi decoding) and RS-LDC decoding at the time of reproduction formthe next-generation MD1 and the next-generation MD2 are provided.

Information detected as reflected light of a laser beam cast on the disc90 from the optical head 22 (i.e., photocurrent obtained as thephotodetector detects the reflected light of the laser beam) is suppliedto an RF amplifier 24. The RF amplifier 24 performs current-voltageconversion, amplification, matrix calculation and the like to theinputted detected information and extracts a reproduction RF signal, atracking error signal TE, a focusing error signal FE, groove information(ADIP information recorded by wobbling of the track on the disc 90) andthe like as reproduction information.

In reproduction from the conventional mini disc, the reproduction RFsignal obtained at the RF amplifier is passed through a comparator 25and a PLL circuit 26 and processed by an EFM demodulator 27 and an ACIRCdecoder 28. The reproduction RF signal is binarized into an EFM signalstring and then EFM-demodulated by the EFM demodulator 27. Moreover,error correction and de-interleave processing are performed to theresulting signal by the ACIRC decoder 28. In the case of audio data,ATRAC compressed data is obtained at this point. In this case, aselector 29 selects a conventional mini disc signal side and thedemodulated ATRAC compressed data is outputted to a data buffer 30 asreproduction data from the disc 90. In this case, the compressed data issupplied to the audio processing unit 19 of FIG. 12.

On the other hand, in reproduction from the next-generation MD1 or thenext-generation MD2, the reproduction RF signal obtained at the RFamplifier is passed through an A/D converter circuit 31, an equalizer32, a PLL circuit 33 and a PRML circuit 34 and processed by anRLL(1-7)PP demodulator 35 and an RS-LDC decoder 36. At the RLL(1-7)PPdemodulator 35, reproduction data as an RLL(1-7) code string is obtainedfrom the reproduction RF signal on the basis of data detection usingPR(1, 2, 1) ML and Viterbi decoding, and RLL(1-7) demodulationprocessing is performed to this RLL(1-7) code string. Moreover, errorcorrection and de-interleave processing are performed by the RS-LDCdecoder 36.

In this case, the selector 29 selects a next-generationMD1/next-generation MD2 side and the demodulated data is outputted tothe data buffer 30 as reproduction data from the disc 90. In this case,the demodulated data is supplied to the memory transfer controller 12 ofFIG. 12.

The tracking error signal TE and the focusing error signal FE outputtedfrom the RF amplifier 24 are supplied to the servo circuit 37. Thegroove information is supplied to the ADIP demodulator 38.

The ADIP demodulator 38 limits the band of the groove information usinga band-pass filter so as to extract a wobble component and then performsFM demodulation and biphasic demodulation to extract an ADIP address. Inthe case of the conventional mini disc or the next-generation MD1, theextracted ADIP address, which is absolute address information on thedisc, is supplied to a drive controller 41 via an MD address demodulator39. In the case of the next-generation MD2, the ADIP address is suppliedto the drive controller 41 via a next-generation MD2 address decoder 40.

The drive controller 41 executes predetermined control processing basedon each ADIP address. The groove information is sent back to the servocircuit 37 for spindle servo control.

The servo circuit 37 generates a spindle error signal for CLV servocontrol and ZCAV servo control, on the basis of an error signal obtainedby integrating a phase difference between the groove information and areproducing clock (PLL clock at the time of decoding).

The servo circuit 37 also generates various servo control signals(tracking control signal, focusing control signal, thread controlsignal, spindle control signal and the like), based on the spindle errorsignal, the tracking error signal and the focusing error signal suppliedfrom the RF amplifier 24 as described above, and a track jump command,an access command and the like from the drive controller 41. The servocircuit 37 outputs these servo control signals to a motor driver 42.That is, the servo circuit 37 performs necessary processing such asphase compensation processing, gain processing and target value settingprocessing in response to the servo error signal and commands, and thusgenerates the various servo control signals.

The motor driver 42 generates predetermined servo drive signals based onthe servo control signals supplied from the servo circuit 37. The servodrive signals of this case include a biaxial drive signal (focusingdirection and tracking direction) for driving the biaxial mechanism, athread motor driving signal for driving the thread mechanism, and aspindle motor driving signal for driving the spindle motor 21. Inresponse to such servo drive signals, focusing control and trackingcontrol on the disc 90 and CLV control or ZCAV control on the spindlemotor 21 are performed.

When the recording operation to the disc 90 is performed, high-densitydata from the memory transfer controller 12 shown in FIG. 12 or normalATRAC compressed data from the audio processing unit 19 is supplied.

In recording to the conventional mini disc, a selector 43 is connectedto a conventional mini disc side, and an ACIRC encoder and an EFMmodulator 45 function. In the case of an audio signal, compressed datafrom the audio processing unit 19 is interleaved and given an errorcorrection code by the ACIRC encoder 44 and then EFM-modulated by theEFM modulator 45. The EFM-modulated data is supplied to a magnetic headdriver 46 via the selector 43 and the magnetic head 23 applies amagnetic field based on the EFM-modulated data to the disc 90, therebyrecording the modulated data.

In recording to the next-generation MD1 and the next-generation MD2, theselector 43 is connected to a next-generation MD1/next-generation MD2side, and an RS-LDC encoder 47 and an RLL(1-7)PP modulator 48 function.In this case, high-density data sent from the memory transfer controller12 is interleaved and given an error correction code of the RS-LDCsystem by the RS-LDC encoder 47 and then RLL(1-7)-modulated by theRLL(1-7)PP modulator 48.

The recording data modulated to the RLL(1-7) code string is supplied tothe magnetic head driver 46 via the selector 43 and the magnetic head 23applies a magnetic field based on the modulated data to the disc 90,thereby recording the data.

A laser driver/APC 49 causes the laser diode to execute a laser beamemitting operation in the reproduction and recording as described above.It also performs a so-called APC (automatic laser power control)operation. Specifically, a detector for monitoring the laser power isprovided in the optical head 22, though not shown, and its monitorsignal is fed back to the laser driver/APC 49. The laser driver/APC 49compares the current laser power acquired as the monitor signal withpredetermined laser power and reflects the difference between them ontoa laser driving signal, thereby controlling the laser power outputtedfrom the laser diode so that the laser power is stabilized at a presetvalue. Values of reproducing laser power and recording laser power areset in a register within the laser driver/APC 49 by the drive controller41.

On the basis of instructions from the system controller 18, the drivecontroller 41 controls each structural unit so that the above-describedoperations (operations of access, various servo, data writing and datareading) are executed. The parts surrounded by chain-dotted lines inFIG. 13 can be constituted as a one-chip circuit.

In the case a data track recording area and an audio track recordingarea are dividedly set on the disc 90 as shown in FIG. 6, the systemcontroller 18 instructs the drive controller 41 of the medium drive unit11 to access a preset recording area in accordance with whether data tobe recorded or reproduced is on an audio track or a data track.

It is also possible to perform control so that recording of only one ofPC data and audio data to the loaded disc 90 is permitted whilerecording of the other data is prohibited. That is, it is possible toperform control so that PC data and audio data do not exist in a mixedmanner.

Thus, the disc drive device 10 described in this embodiment has theabove-described structure and therefore can realize compatibilitybetween the conventional mini disc, the next-generation MD1 and thenext-generation MD2.

5. Sector Reproduction Processing on Data Track

Reproduction processing and recording processing to the next-generationMD1 and the next-generation MD2 by the above-described disc drive device10 will now be described. In access to a data area, an instruction torecord or reproduce data by each “logical sector (hereinafter referredto as FAT sector)” is given, for example, from the external PC 100 tothe system controller 18 of the disc drive device 10 via the USBinterface 16. A data cluster, as viewed from the PC 100, is sectionedevery 2048 bytes and managed on the basis of the FAT file system in USNascending order, as shown in FIG. 7. On the other hand, the minimumrewriting unit of a data track on the disc 90 is a next-generation MDcluster having a size of 65,536 bytes, and this next-generation MDcluster is provided with LCN.

The size of a data sector referred to by FAT is smaller than that of anext-generation MD cluster. Therefore, in the disc drive device 10, auser sector referred to by FAT must be converted to a physical ADIPaddress and reading/writing of data by each data sector referred to byFAT must be converted to reading/writing of data by each next-generationMD cluster, using the cluster buffer memory 13.

FIG. 14 shows the processing in the system controller 18 of the discdrive device 10 in the case a reading request for a certain FAT sectoris sent from the PC 100.

When the system controller 18 receives a reading command for FAT sector#n from the PC 100 via the USB interface 16, the system controller 18performs processing to find the next-generation MD cluster number of thenext-generation MD cluster containing the FAT sector of the designatedFAT sector number #n.

First, provisional next-generation MD cluster number u0 is decided. Thesize of a next-generation MD cluster is 65,536 bytes and the size of aFAT sector is 2048 bytes. Therefore, 32 FAT sectors exist in onenext-generation MD cluster. FAT sector number (n) divided by 32 with theremainder rounded down, that is, u0, becomes the provisionalnext-generation MD cluster number.

Then, with reference to the disc information read into the auxiliarymemory 14 from the disc 90, the number of next-generation MD clusters uxother than the clusters for data recording is found. That is, the numberof next-generation MD clusters in the secure area is found.

As described above, some of the next-generation MD clusters in the datatrack are not made public as a data recordable/reproducible area.Therefore, the number of non-public clusters ux is found on the basis ofthe disc information read into the auxiliary memory 14 in advance. Afterthat, the number of non-public clusters ux is added to next-generationMD cluster number u0, and the result of addition u is used as actualnext-generation MD cluster number #u.

As next-generation MD cluster number #u of the next-generation MDcluster containing FAT sector number #n is found, the system controller18 judges whether or not the next-generation MD cluster of clusternumber #u has already been read out from the disc 90 and stored in thecluster buffer memory 13. If not, the system controller 18 reads it fromthe disc 90.

The system controller 18 finds ADIP address #a from the read-outnext-generation MD cluster number #u and thus reading out thenext-generation MD cluster from the disc 90.

The next-generation MD cluster might be dividedly recorded in pluralpart on the disc 90. Therefore, to find the ADIP address where it isrecorded, these parts must be sequentially searched. Thus, from the discinformation read out into the auxiliary memory 14, the number ofnext-generation MD clusters p recorded in the leading part of the datatrack and the leading next-generation MD cluster number px are found.

Since the start address/end address is recorded in the form of ADIPaddress in each part, the number of next-generation MD clusters p andthe leading next-generation MD cluster number px can be found from theADIP cluster address and the part length. Next, it is judged whetherthis part includes the next-generation MD cluster of the target clusternumber #u or not. If not, the next part is searched. That is, the partindicated by link information of the previously considered part issearched. In this manner, the parts described in the disc informationare sequentially searched and the part containing the targetnext-generation MD cluster is discriminated.

When the part in which the target next-generation MD cluster (#u) isrecorded is found, the difference between next-generation MD clusternumber px recorded at the leading end of this part and the targetnext-generation MD cluster number #u is found and an offset from theleading end of the part to the target next-generation MD cluster (#u) isthus acquired.

In this case, since two next-generation MD clusters are written in oneADIP cluster, this offset may be divided by 2 and thus converted to anADIP address offset f (where f (u-px)/2).

However, if a fraction of 0.5 is generated, writing starts at a centralpart of the cluster f Finally, the offset f is added to the clusteraddress part at the leading ADIP address of this part, that is, at thestart address of the part, and ADIP address #a of the recordingdestination to which the next-generation MD cluster (#u) is to beactually written can be thus found. The processing up to this point isequivalent to the processing to set the reproduction start address andthe cluster length at step S1. In this case, it is assumed thatdiscrimination of the conventional mini disc, the next-generation MD1 orthe next-generation MD2 has already been completed.

As ADIP address #a is found, the system controller 18 instructs themedium drive unit 11 to access ADIP address #a. Therefore, the mediumdrive unit 11 executes access to ADIP address #a under the control ofthe drive controller 41.

The system controller 18 waits for completion of the access at step S2.On completion of the access, the system controller 18 at step S3 waitsfor the optical head 22 to read the target reproduction start address.After confirming at step S4 that the optical head 22 has reached thereproduction start address, the system controller 18 at step S5instructs the medium drive unit 11 to start data reading of one clusterof the next-generation MD clusters.

In response to this, the medium drive unit 11 starts data reading fromthe disc 90 under the control of the drive controller 41. Data readoutby the reproducing system including the optical head 22, the RFamplifier 24, the RLL(1-7)PP demodulator 35 and the RS-LDC decoder 36 isoutputted and supplied to the memory transfer controller 12.

At this point, the system controller 18 at step S6 judges whethersynchronization with the disc 90 is realized or not. If synchronizationwith the disc 90 is not realized, the system controller 18 at step S7generates a signal indicating occurrence of a data reading error. If itis determined at step S8 that reading is to be executed again, theprocesses from step S2 are repeated.

When the data of one cluster is acquired, the system controller 18 atstep S10 starts error correction of the acquired data. If the acquireddata has an error at step S11, the system controller 18 returns to stepS7 to generate a signal indicating occurrence of a data reading error.If the acquired data has no error, the system controller 18 at step S12judges whether a predetermined cluster has been acquired or not. If thepredetermined cluster has been acquired, the series of processing endsand the system controller 18 waits for the medium drive unit 11 tocomplete the reading operation and causes the data read out and suppliedto the memory transfer controller 12 to be stored into the clusterbuffer memory 13. If the predetermined cluster has not been acquired,the processes from step S6 are repeated.

The data of one cluster of the next-generation MD clusters read into thecluster buffer memory 13 contains plural FAT sectors. Therefore, thedata storage position of the requested FAT sector is found from these,and the data of the one FAT sector (2048 bytes) is sent to the externalPC 100 from the USB interface 15. Specifically, the system controller 18finds, from the requested FAT sector number #n, byte offset #b in thenext-generation MD cluster containing this sector. Then, the systemcontroller 18 causes the data of the one FAT sector (2048 bytes) fromthe position of byte offset #b in the cluster buffer memory 13 to beread out, and transfers the read-out data to the PC 100 via the USBinterface 15.

By the above-described processing, reading and transfer of anext-generation MD sector corresponding to a reading request for one FATsector from the PC 100 can be realized.

6. Sector Writing Processing on Data Track The processing in the systemcontroller 18 of the disc drive device 10 in the case a writing requestfor a certain FAT sector is sent from the PC 100 will now be describedwith reference to FIG. 15.

When the system controller 18 receives a writing command for FAT sector#n from the PC 100 via the USB interface 16, the system controller 18finds the next-generation MD cluster number of the next-generation MDcluster containing the FAT sector of the designated FAT sector number #nas described above.

As next-generation MD cluster number #u of the next-generation MDcluster containing FAT sector number #n is found, the system controller18 judges whether or not the next-generation MD cluster of the foundcluster number #u has already been read out from the disc 90 and storedin the cluster buffer memory 13. If not, the system controller 18performs processing to read out the next-generation MD cluster ofcluster number u from the disc 90. That is, the system controller 18instructs the medium drive unit 11 to read out the next-generation MDcluster of cluster number #u and to store the read-out next-generationMD cluster into the cluster buffer memory 13.

Moreover, the system controller 18 finds, from FAT sector number #n ofthe writing request, byte offset #b in the next-generation MD clustercontaining this sector, in the above-described manner. Then, the systemcontroller 18 receives data of 2048 bytes as writing data to the FATsector (#n) transferred from the PC 100 via the USB interface 15, andstart writing the data of one FAT sector (2048 bytes) at the position ofbyte offset #b in the cluster buffer memory 13.

Therefore, of the data of the next-generation MD cluster (#u) stored inthe cluster buffer memory 13, only the FAT sector (#n) designated by thePC 100 is rewritten. Thus, the system controller 18 performs processingto write the next-generation MD cluster (#u) stored in the clusterbuffer memory 13 to the disc 90. The processing up to this point is arecording data preparation process of step S21. In this case, too, it isassumed that discrimination of the medium has already been completed byanother technique.

Next, the system controller 18 at step S22 sets ADIP address #a of therecording start position from next-generation MD cluster number #u forwriting. As ADIP address #a is set, the system controller 18 instructsthe medium drive unit 11 to access ADIP address #a. Therefore, themedium drive unit 11 executes access to ADIP address #a under thecontrol of the drive controller 41.

After confirming completion of the access at step S23, the systemcontroller 18 at step S24 waits for the optical head 22 to reach thetarget reproduction start address. As it is confirmed at step S25 thatthe optical head has reached the encode address of the data, the systemcontroller 18 at step S26 instructs the memory transfer controller 12 tostart transferring the data of the next-generation MD cluster (#u)stored in the cluster buffer memory 13 to the medium drive unit 11.

Then, after confirming at step S27 that the recording start address hasbeen reached, the system controller 18 at step S28 instructs the mediumdrive unit 11 to write the data of this next-generation MD cluster tothe disc 90. In response to this, the medium drive unit 11 starts datawriting to the disc 90 under the control of the drive controller 41.That is, the data transferred from the memory transfer controller 12 isrecorded by the recording system including the RS-LDC encoder 47, theRLL(1-7)PP modulator 48, the magnetic head driver 46, the magnetic head23 and the optical head 22.

At this point, the system controller 18 at step S29 judges whethersynchronization with the disc 90 is realized or not. If synchronizationwith the disc 90 is not realized, the system controller 18 at step S30generates a signal indicating occurrence of a data reading error. If itis judged at step S31 that reading is to be executed again, theprocesses from step S2 are repeated.

When data of one cluster is acquired, the system controller 18 at stepS32 judges whether a predetermined cluster has been acquired or not. Ifthe predetermined cluster has been acquired, the series of processingends.

By the above-described processing, writing of FAT sector data to thedisc 90 corresponding to a writing request for one FAT sector from thePC 100 can be realized. In short, writing of data by each FAT sector isexecuted as rewriting of data by each next-generation MD cluster to thedisc 90.

7. Relation Between ADIP Address and Address of Address Unit

The relation between the ADIP address and the address of the addressunit will now be described with reference to FIGS. 16 and 17. In theseFIGS. 16 and 17, AC represents the cluster address (cluster number)based on the above-described ADIP, which is the physical address on thedisc, and AU represents the address of the above-described address unitfor accessing data. FIG. 16 shows the case of the next-generation MD1.FIG. 17 shows the case of the next-generation MD2.

First, in FIG. 16, since the next-generation MD1 uses the ADIP of theconventional MD, 16 bits of AC0 to AC15 are used as the clusteraddresses (cluster number).

In FIG. 16, AC represents the cluster address and AD represents theaddress sector. In consideration of a recording capacity ofapproximately 80 minutes as an actually used MD, it suffices to providea cluster address of approximately 12 bits. AC0 to AC14 of this ADIPcluster address are associated with address bits AU6 to AU20 of theaddress unit.

As the ADIP address of the conventional MD, a sector address of 8 bitsis arranged on the lower side of the cluster address. On the basis ofthis sector address, 0/1 expressing the sector address (FC to 0D) of theformer-half cluster and the sector address (0E to 1F) of the latter-halfcluster shown in FIG. 9 is associated with address bit AU5 of theaddress unit.

That is, this address bit AU5 has a value 0 in the case of theformer-half cluster (sectors FC to 0D) and 1 in the case of thelatter-half cluster (sectors 0E to 1F). This address bit AU5 of theaddress unit becomes the least significant bit of the address of theabove-described recording unit, and AU5 to AU20 represent the recordingblock number or recording block address. To a part 110 of 4 bits ofaddress bits AU4 to AU1 below address bit AU5, bits generated by a 4-bitcounter are allocated. That is, 4 bits for representing respective partsin the case where the above-described one recording block of FIG. 9 isequally divided by 16 are represented by address bits AU4 to AU1,respectively.

More specifically, the parts obtained equally dividing 496 frames offrame 10 to frame 505 as a data area, of 512 frames of one recordingblock of FIG. 9, by 16, are accessed with AU4 to AU1, respectively.

The least significant bit AU0 constantly has a value 0. In this specificembodiment, the number of bits of the address unit is 25, and the value(code) of AC14 of the ADIP address is substituted into AU21 to AU23,which are above AU20. Alternatively, the value of AU20 of the addressunit may be substituted into AU21 to AU23. Moreover, the value (code) ofAC14 may be substituted into AU20, and the value (code) of AC15 may besubstituted into AU21 to AU23.

In consideration of a disc having plural recording areas for land/grooverecording or two-spiral track recording, or a double-layer disc, anaddress bit ABLG for identifying these recording areas is provided.Thus, AU0 to AU23 and ABLG constitute an address of 25 bits.

In the leading three frames of 31 frames constituting address unitsobtained by equally dividing 496 frames of FIG. 9 by 16, theabove-described address unit number of 25 bits is recorded. This 25-bitaddress unit number may also be written into, for example, a part of theBIS area of FIG. 3 in a predetermined cycle (for example, a cycle of 31frames).

FIG. 20 shows the structure for realizing conversion from the clusteraddress to the unit address in the next-generation MD1. The numbersprovided in FIG. 20 partly correspond to the numbers in FIG. 13.

The ADIP address demodulated by the ADIP demodulator 38 is converted bythe MD address demodulator 39 to an address of 20 bits in totalincluding cluster H, cluster L and sector. For the 16 bits (AC 15 toAC0) of cluster H and cluster L, an identifier is generated by a formercluster/latter cluster identifier generator circuit 411 and registeredto AUS by an address unit generator circuit 413.

Addresses generated for respective recording units by a recording blockaddress generator circuit 412 are registered to AU1 to AU4 by theaddress unit generator circuit 413. The ADIP address demodulated by theADIP demodulator 38 is duplicated to AC8 to AC23 by the MD addressdemodulator 39, and cluster H and cluster L are partly duplicated to AC8to AC23 by the address unit generator circuit 413.

0 is registered to AU0 and the address bit ABLG generated by the addressunit generator circuit 413 is registered to AU25. The address unitnumber generated by the address unit generator circuit 413 istransmitted to the data buffer 30, then modulated in a predeterminedmanner, and recorded for plural times into the leading three frames of31 frames constituting each address unit.

In the specific example shown in FIG. 16, a disc having one recordingarea is used and ABLG is 0. However, in the case of a disc having tworecording areas, 1 or 0 is given in accordance with the individualrecording areas. In the case of a disc having three or more recordingareas, two or more address bits for identifying the recording areas maybe provided.

Next, in the case of the next-generation MD2 shown in FIG. 17, since anADIP cluster includes 16 sectors, AC0 to AC15 of the cluster address(cluster number) of the ADIP address are associated with AU5 to AU20 ofthe address unit. Also in this case, address bit AU5 of the address unitbecomes the least significant bit of the address of the above-describedrecording unit, and AU5 to AU20 represent the recording block number orrecording block address. To a part 110 of 4 bits of address bits AU4 toAU1 below address bit AU5, bits generated by a 4-bit counter areallocated. The least significant bit AU0 constantly has a value 0.Moreover, the value (code) of AC15 of the ADIP address is substitutedinto AU21 to AU23, which are above AU20.

Also in this specific example shown in FIG. 17, similar to the case ofFIG. 16, ABLG is constantly 0 corresponding to a disc having onerecording area. However, in the case of a disc having two recordingareas, 1 or 0 is given in accordance with the individual recordingareas. In the case of a disc having three or more recording areas, twoor more address bits for identifying the recording areas may beprovided.

The specific circuit in the case of FIG. 17 is the same as that of FIG.20 except for the former cluster/latter cluster identifier generatorcircuit 411, which is not provided in this case.

According to this embodiment of the present invention, thenext-generation DM1 enables data access using the 25-bit address (AU0 toAU25) extended for handling an increased data volume while using thesame physical address format as that of the conventional MD. Thenext-generation MD1 thus has excellent compatibility and enables accessto an increased volume of data without causing any inconvenience.Moreover, between the next-generation MD1 and the next-generation MD2,excellent data compatibility is realized as the 25-bit address (AU0 toAU25) of the address unit can be equally handled.

8. Scrambling Processing for Each Sector (Logical Sector) of Data

Scrambling processing for each sector (logical sector) of data will nowbe described with reference to FIGS. 18 and 19. In FIGS. 18 and 19, ACrepresents the cluster address (cluster number) based on theabove-described ADIP, which is the physical address on the disc. AUrepresents the address of the address unit for accessing data, and srepresents each bit of a shift register for generating a pseudo-randomnumber. FIG. 18 shows the case of the next-generation MD1. FIG. 19 showsthe case of the next-generation MD2.

In the description of FIG. 2, 2052 bytes, obtained by adding 4-byte EDC(error detection code) to every 2048 bytes of user data supplied from ahost application or the like, is handled as one sector (data sector orlogical sector), and 32 sectors from sector 0 to sector 31 are groupedas a block consisting of 304 columns and 216 rows. For data of 2052bytes of each sector, a pseudo-random number is generated using the ADIPaddress as a seed or initial value of random number, and exclusive OR(EX-OR) with this pseudo-random number is taken to perform scramblingprocessing. The pseudo-random number may be generated from, for example,a so-called maximum length sequence using a generating polynomial, andthe seed of random number is loaded as an initial value to a shiftregister for generating the maximum length sequence. The seed of randomnumber may be, for example, the cluster address (cluster number) of theADIP address but it is not limited to this number. However, in theembodiment of the present invention, in consideration of a disc havingplural recording areas for land/groove recording or two-spiral trackrecording, or a double-layer disc, identification information of theserecording areas, for example, address bit ABLG for land/grooveidentification in FIGS. 18 and 19, may be used as a part of the seed ofrandom number.

The data unit of 2048 bytes is called user data sector, and the dataunit of 2052 bytes with the EDC added thereto is called data sector.

Specifically, first, in the case of the next-generation MD1 shown inFIG. 18, AC0 to AC12 of the cluster address of ADIP are associated withAU6 to AU18 of the address unit. A high-order digit of the sectoraddress, which is 0 in the case of the former-half cluster (FC to 0D)and is 1 in the case of the latter-half cluster (0E to 1F), isassociated with AU5. The address bit ABLG for identifying the recordingareas of the disc having plural recording areas for land/grooverecording or the like is set at 0. These bits of AU5 to AU18 and ABLGare associated with 15 bits s0 to s14 from the lower side in the 16-bitshift register for generating a pseudo-random number. Considering that apseudo-random number cannot be generated if all the bits of the shiftregister become 0, 1 is associated with the most significant bit s15.The values of these bits AU5 to AU18 and ABLG and the value 1 for themost significant bit are loaded to the bits s0 to s15 of the 16-bitshift register every time the data sector of FIG. 2 starts. This is usedas an initial value and a pseudo-random number is generated. Then,exclusive OR (Ex-OR) of the generated pseudo-random number and each dataof the data sector is taken.

Next, in the case of the next-generation MD2 shown in FIG. 19, AC0 toAC13 of the cluster address of ADIP are associated with AU5 to AU18 ofthe address unit. The address bit ABLG for identifying the recordingareas of the disc having plural recording areas for land/grooverecording or the like is set at 0. These bits of AU5 to AU18 and ABLGare associated with 15 bits s0 to s14 from the lower side in the 16-bitshift register for generating a pseudo-random number. Considering that apseudo-random number cannot be generated if all the bits of the shiftregister become 0, 1 is associated with the most significant bit s15.The values of these bits AU5 to AU18 and ABLG and the value 1 for themost significant bit are loaded to the bits s0 to s15 of the 16-bitshift register every time the data sector of FIG. 2 starts. This is usedas an initial value and a pseudo-random number is generated. Then,exclusive OR (Ex-OR) of the generated pseudo-random number and each dataof the data sector is taken.

In the above-described specific examples, 16 bits obtained by connectingthe cluster address (recording block number), the address bit ABLG forrecording area identification and 1 of the most significant position areuses as a seed of random number, and it is loaded as an initial value tothe 16-bit shift register for pseudo-random number generation every timethe data sector of FIG. 2 starts, thus generating a pseudo-randomnumber. However, the address is not limited to the cluster address(recording block number) and may include, for example, a part of theaddress below AU5. The timing at which the seed of random number isloaded is not limited, either. In the case of a disc having tworecording areas, 1 or 0 is given in accordance with the individualrecording areas. In the case of a disc having three or more recordingareas, two or more address bits for identifying the recording areas maybe provided.

According to the embodiment of the present invention, as scramblingprocessing is performed to digital data in which a bias is easilygenerated because of the regularity of the data or the like, randomnessis realized and the recording/reproducing efficiency is improved.Moreover, even in the case of a disc having plural recording areas suchas a land/groove recording disc or a multilayer disc and thus having thesame address on the neighboring tracks, since the seed for generation ofrandom number differs between the recording areas, no same random numberis generated and different scrambling processing is performed.Therefore, interference between tracks can be reduced.

It should be understood by those ordinarily skilled in the art that theinvention is not limited to the above-described embodiment describedwith reference to the drawings, but various modifications, alternativeconstructions or equivalents can be implemented without departing fromthe scope and spirit of the present invention as set forth and definedby the appended claims.

Industrial Applicability

In the present invention, the word length of first address informationis set to be longer than the word length of second address informationand a part of the first address information is duplicated to the secondaddress information. An address is added to each high-density block andconverted to the second address information. Thus, data can be recordedin plural recording formats to a recording medium on which the firstaddress information is modulated in a predetermined manner and recordedin advance, and a higher-density data volume can be handled withoutcausing any inconvenience while using the existing recording format.

1. A disc recording/reproducing device adapted for, with respect to a disc on which a unit cluster having a predetermined number 2N (where N is a positive integer) of sectors as a set is formed and on which a sector address corresponding to each sector and a cluster address corresponding each cluster are modulated in a predetermined manner and recorded in advance, performing recording and reproduction using N sectors as a unit, which is obtained by bisecting the unit cluster, the disc recording/reproducing device comprising: reproduction means for reproducing the cluster address and the sector address modulated in the predetermined manner and recorded in advance, from the disc; identifier generation means for generating an identifier that identifies the former N sectors or the latter N sectors obtained by bisecting the cluster unit, as a recording unit used for recording data; recording means for blocking inputted data into plural blocks and recording the blocked data within the N-sector recording unit; address generation means for generating an address corresponding to the plural blocks each that are formed in the N-sector recording unit; and conversion means for converting the cluster address and the sector address reproduced by the reproducing means to an address unit including the identifier generated by the identifier generation means, the address generated by the address generation means and a recording block address generated on the basis of the cluster address; the address unit obtained by conversion by the conversion means being recorded for the plural blocks each, by the recording means. 